Linux: Look for assets directory in /usr/share/ppsspp/.
Merge pull request #6692 from Barthalion/systemwide-assets

Linux: Look for assets directory in /usr/share/ppsspp/.
Correctly break when disabled and temp bps overlap.

Only affects debugging, not usual gameplay.  Fixes #6700.
Reduce Sybmian parallel build for Travis.

May help reduce the random failures.
Add "Screen Scaling Filter" option